A major area of interest in the fragrance industry is to find high odour impact fragrance materials which can provide superior performance at lower concentrations giving cost savings and lower environmental impact.
Muguet (Lily of the Valley) is an important area in perfumery (M Boelens and H Wobben, Perfumer & Flavorist, 1980, 5 (6), 1-8) and the odour is created by a combination of fragrance ingredients, of which 3-(3/4-alkylphenyl)propanals such as
Bourgeonal™ (3-(4-tert-butylphenyl)propanal, U.S. Pat. No. 2,976,321),
Florhydral™ (3-(3-isopropylphenyl)butanal, EP 368156),
Lily Aldehyde™ (3-4-tert-butylphenyl)-2-methylpropanal, U.S. Pat. No. 2,875,131) and
Cyclamen Aldehyde™ (3-(4-isopropylphenyl)-2-methylpropanal, U.S. Pat. No. 1,844,013) provide floral, green and in particular watery aspects. All of these materials are used in Muguet accords in high volumes to good effect.
The relationship between molecular structure and odour has intrigued and perplexed scientists for two and a half millennia since Democritus and Epicurus first postulated a causal relationship among philosophical circles in Athens. The ability to accurately and consistently predict the odour of putative molecules from their molecular structure continues to prove elusive. Recent developments (which led to the award of a Nobel Prize) in molecular biology have now given an insight into the reasons behind this. Discovery of the gene family encoding for olfactory receptor proteins (L. B. Buck and R. Axel, Cell, 1991, 65, 175-187) paved the way for confirmation that the sense of smell is combinatorial in nature and uses an array of hundreds of different receptor types. (B. Malnic, J. Hirono, T. Sato and L. B. Buck, Cell, 1999, 96, 713-723) Some of the issues raised by this in terms of odorant design are described by no less a figure than another Nobel Laureate E. J. Corey in a paper on the understanding of odorant-receptor interaction. (S. Hong and E. J. Corey, J. Amer. Chem. Soc., 2006, 128, 1346-1352). A review on the subject shows that, far from making rational odorant design easier, this new understanding indicates that accurate and consistent prediction of odour properties will remain beyond our grasp for the foreseeable future. (C. S. Sell, Angew. Chem. Int. Edn., 2006, 45, 6254-6261) Furthermore, an essay on property prediction from molecular structure (M. Jansen and J. C. Schoen, Angew. Chem. Int. Edn., 2006, 45, 3406-3412) suggests that, at an even deeper level, all chemical properties of a proposed structure are not accurately and consistently predictable.
In a study made by R Pelzer et al (R Pelzer, U Harder, A Krempel, H Sommer, S Surburg and P Hoever in Recent Developments in Flavour & Fragrance Chemistry Proceedings of the 3rd International Haarmann & Reimer Symposium, Ed R Hopp and K Mori, VCH, 1993 pp 29-67), 181 substances possessing different aspects of the Lily of the Valley fragrance were investigated with the use of computer models. For the aldehydic materials, 41 in total, the generic fragment structure
was developed and it was stated, amongst other requirements, that “a double bond at C-4 is particularly advantageous, and may also be part of an aromatic system”.
There are a smaller number of aldehydic materials that are non-aromatic and possess Muguet-like odours but these tend to have alicyclic terpinoid-like structures such as Trimenal.

EP 1054053 A discloses non-aromatic aldehydes with the generic structure of:
where R=H or Me, the dotted line representing either a double or single bond and n=0 (when dotted line represents a single bond) and 1 (when the dotted line represents a double bond). In the latter case, the material was described as having an aldehydic, flowery-lily of the valley, fatty type of odour with a Lily Aldehyde™/Bourgeonal™ connotation but is described as definitely more floral, more white flower than that of Lily Aldehyde™. This molecule also fits the Pelzer model in that unsaturation is present at the C-4 position.
3-(3-methylcyclohexyl)propanal is disclosed in “Sur l'addition radiculaire d'acide bromhydrique, sur quelques composés allyliques cycloniques en présence de peroxyde de diterbutyle. Réactions de substitution sur les bromures”, J-M Pabiot and R Pallaud, C. R. Acad. Sc. (1971), 273(6), 475-7. However no odour properties are disclosed.